Saturday, 13 June 2015

Kurt Kurzweil's Systemhood Argument vs. Searle's Chinese Room Argument

In his rewarding book, How to Create a Mind, Ray Kurzweil covers John Searle's Chinese room argument.

It's a great book; though I do find its philosophical sections somewhat unskilled. And that's despite the book's abundance of scientific and technical detail, as well as Kurzweil's imaginative capabilities. Having said that, there's no reason why a “world-renowned inventor, thinker and futurist” should also be an accomplished philosopher. (There's also a danger of philosophers criticising him for not being so.) Indeed I've detected a certain about of snobbery (or elitism) directed at Ray Kurzweil from philosophers and scientists; which is, I think, partly down to him being neither an academic scientist nor a academic philosopher.

Partly as a result of that, Kurzweil says, for example, that all critics tend to know about Watson (an “artificially intelligent computer system capable of answering questions posed in natural language”) is that it's a computer in a machine. He also says that some commentators don't “acknowledge or respond to arguments I actually make”. He adds:

I cannot say that Allen and similar critics would necessarily have been convinced by the argument I made in that book [The Singularity is Near], but at least he and others could have responded to what I actually wrote.” (267)

The problem is that, in the case of Searle's Chinese room argument, you can say the same about Ray Kurzweil case against Searle. Then again, you wouldn't expect a full-frontal and elongated response to Searle in a popular science book like How to Create a Mind. Having said that, there is a great deal of detail and some complexity - when it comes to other issues and subjects - found in this book.

The Argument

Ray Kurzweil's argument against Searle is extremely simple. He simply makes a distinction between Searle's man in the Chinese room and that man's rulebook. The man on his own doesn't understand Chinese. The man and the rulebook, taken together, do understand Chinese.

However, instead of talking about a man and his rulebook, let's talk about the central processing unit (CPU) of a computer and its rulebook (or set of algorithms). After all, this is all about human and computer minds.

Firstly, Kurzweil says that “the man in this thought experiment is comparable only to the central processing unit (CPU) of a computer” (275). However, “but the CPU is only part of the structure”. In Searle's Chinese room, “it is the man with his rulebook that constitutes the whole system”.

Again, the “system does have an understanding of Chinese”; though the man (or CPU?) on its own doesn't.

The immediate reaction to this is how bringing two things (a man and a rulebook) together can, in and of itself, automatically bring about a system's understanding of Chinese. Why is a system of two or more parts in a better position than a system with one part? (That's if, on this reading, a system can have only one part.) How and why does multiplicity and (as it were) systemhood bring about understanding? It can be said that the problem of (genuine) understanding has simply been replicated. It may indeed be the case that the addition of a rulebook to either a man or a CPU brings about true understanding; it's just that Kurzweil doesn't really say why it does so.

Searle is of course aware of what may be called the whole-system argument. Nonetheless, he doesn't quite talk about the same system as Kurzweil. Instead of a man and a rulebook (or a CPU and a set of algorithms), Searle (in his paper 'Minds, brains, and programs' -1980) writes:

Suppose we put a computer inside a robot.... the computer would actually operate the robot in such a way that the robot does something very much like perceiving, walking, moving about.... The robot would, for example, have a television camera attached to it that enabled it to 'see'....”

As I said, this system isn't the same as Kurzweil's: its more complex and has more parts. Thus, on Kurzweil's own reasoning, it should stand more of a chance of being a mind (or even person) than a computer's CPU and its set of algorithms.

Searle then talks about putting himself in the robot instead of a computer. However, neither scenario works for Searle. It's still a case that all Searle-in-the-robot is doing is “manipulating formal symbols”. Indeed Searle is simply

the robot's homunculus, [he] doesn't know what's going on. [He doesn't] understand anything except the rules for symbol manipulation”.

Again, how does systemhood alone deliver understanding?

Ned Block on Systemhood

Ned Block, on the other hand, offers us a system which is very similar to Kurzweil's. He too is impressed with the systemhood argument. In his 'The Mind as Software in the Brain' he says that

we cannot reason from 'Bill does not understand Chinese' to 'The system of which Bill is a part does not understand Chinese.'”

Block continues by saying that

the whole system – man + programme + board + paper + input and output doors – does understand Chinese, even though the man who is acting as the CPU does not”.

Block adds one more point to the above. He writes:

I argued above that the CPU is just one of many components. If the whole system understands Chinese, that should not lead us to expect the CPU to understand Chinese.”

Again, how does systemhood automatically generate understanding? Block hardly offers an argument other than complexity or that the addition of parts to a system may (or does) bring about understanding. Indeed he goes so far as to say that his own system could (or does) have what he calls “thoughts”. He writes that

Searle uses the fact that you are not aware of the Chinese system's thoughts as an argument that it has no thoughts. But this is an invalid argument. Real cases of multiple personalities are often cases in which one personality is unaware of the others”.

Indeed a part of Block's argument does seem to be correct. It doesn't appear to be the case that if Searle-in-the-system doesn't know the thoughts of the entire system that consequently the system must have no thoughts either. That much seems acceptable. Nonetheless, the question still remains as to how mere systemhood brings about understanding. It doesn't matter if the CPU or Searle-in-the-system does or does not know what the entire system is thinking (or understanding) if mere systemhood can't bring about thoughts (or understanding) in the first place. In other words, Searle-in-the-system (or the CPU) may in principle be unable to know if the system as a whole has thoughts (or understands things) and yet at the same time it's still the case that it doesn't have thoughts (or understand things).

Kurzweil's Computer-Behaviourism?

Kurzweil says something that simply begs the question in its simplicity. He writes:

That system [of a man and his rulebook] does have an understanding of Chinese; otherwise it would not be capable of convincingly answering questions in Chinese, which would violate Searle's assumption for this thought experiment.”

What Kurzweil seems to be arguing is that if the system answers the questions, then, almost (or literally) by definition, it must understand the questions. Full stop. This is a kind of behaviourist (or perhaps functionalist) answer to the problem. If the system behaves as if it understands (i.e., by answering the questions), then it understands. Indeed it's not even really a question of “behaving as if” it understands. If the system answers the questions, it does understand because if it didn't understand, it couldn't answer the questions!

Searle is of course aware of this behaviourist (or at least quasi-behaviourist) position. Basically, the problem of computer minds replicates the problem of human “other minds”. As Searle himself puts it:

'How do you know that other people understand Chinese or anything else? Only by their behaviour. Now the computer can pass the behavioural tests as well as they can (in principle), so if you are going to attribute cognition to other people, you must in principle also attribute it to computers.'”

As I said, this begs all Searle's questions about true understanding – or, in his terms, meaning, intentionality and reference. To put the Searlian point in very basic terms: the system could answer the questions without understanding the questions. Though since Kurzweil is arguing that the very act of answering the questions quite literally constitutes understanding; then, by definition, Searle is wrong. Nothing, according to Kurzweil, is missing from the story.

So forget the man and his rulebook, let's talk about the CPU and its rulebook (or set of algorithms) instead. If the CPU and the rulebook answer the questions, it understands the questions. In other words, the computer understands the questions.

If it's definitionally the case that answering the questions means understanding the questions, then Kurzweil is (again, by definition) correct in his argument against Searle. Nonetheless, Searle knows that this is the argument and he's argued against it for decades. There's something left out or wrong about Kurzweil's position. So what's wrong with it?

Kurzweil himself is aware - if in a rudimentary form - of what Searle will say in response. Writing of Searle's position, Kurzweil says that

he states that Watson is only manipulating symbols and does not understand the meaning of those symbols”. (170)

It does indeed eem obviously the case that this is just a case of “manipulating symbols” and not one of true understanding. Having said that, that obviousness (or acquired, as it were, intuition) is probably largely a result of reading Searle and other philosophers on this subject. If I had read more scientists (or at least some of them) on this subject, it may seem that what Kurzweil argues is obviously the case.

So let's forget intuition or obviousness.

Does a thermometer understand heat because it reacts to it in the same way each time? It's given a question (heat) and provides an answer (the rising or falling mercury). Sure, this understanding is non-propositional and doesn't involve words or even symbols. But if Kurzweil himself sees these things in terms of the brain, its physical nature and output (behaviour) and not in terms of meaning or sentences, then why should that matter to him? In other words, if we can judge a computer squarely in terms of its output or behaviour (answering questions), then we can judge the thermometer in the same way. According to Kurzweil, if the computer answers questions then, by definition, it understands. Thus if the thermometer responds in the right way to different levels of heat, then it too understands. Sentences and their meanings are no more important to computers than they are to thermometers.*

*) Paul Churchland, tangentially, argues the same about minds/brains and what he calls “propositional attitudes”.

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